Refrigeration



March 17, 1942. R THOMAS REFRIGERATION Filed July 16, 1938 2Sheets-Sheet l IA'YENTOR. BY Md T/www A, A ATTORNEY.

March 17, 1942; R THOMAS I 2,276,434-

REFRIGERATION Filed Jul 16, 1938 '2 Sheets-Sheet 2 INVENTQR.

MATTORNEY.

Patented Mar. 17, 1942 UNITED STATES PATENT OFFICE REFRIGERATION AlbertR. Thomas, Evansville, Ind., assignor to Servel, Inc., New York, N. Y.,a corporation of Delaware Application July 16, 1938, Serial No. 219,511

8 Claims.

- therewith, and condenses in a condenser or heat rejecting portion andgives up heat to a medium in thermal exchange-relation therewith.

It is an object of the invention to provide an improvement in systems ofthis type for raising liquid heat transfer fluid from a heat rejectingportion at a lower elevation to a heat receiving portion at an upperelevation. Broadly, this is accomplished by circulating a working fluidin a heat transfer system by vapor lift action, and causing circulationof heat transfer fluid by circulation of the working fluid.

The working fluid preferably is of greater to Fig. 2 illustrating amodification of the invention.

In Fig. 1 the heat transfer system embodying the invention is shown inconnection with a cooling element or evaporator III of a primaryrefrigeration system of a uniform pressure type, and like that describedin my application Serial No. 107,852, filed October 27, 1936. Thecooling. element i0 constitutes asource of refrigeration and includes acasing Ii which may be embedded in insulation l2. Liquid refrigerant,such as ammonia, enters the upper part of cooling element l0 through aconduit 13. An inert gas, such as hydrogen, enters the upper part ofcasing I I from the upper end of a cylinder l4 disposed therein. Liquidrefrigerant evaporates and diffuses into inert gas within casing II toproduce arefrig 1 erating effect.

specific weight than the heat transfer fluid and flows in a localcircuit in the system. Circulation of working fluid in the local circuitis effected by vapor lift action, and slugs of working fluid are formedas a result of such vapor lift action. The slugs of working fluid areutilized to segregate small bodies of liquid heat transfer fluid whichare subsequently separated from the working fluid at the lower end of aliquid column of the working fluid. This column of working fluid reactsagainst the riser column of separated liquid heat transfer fluid andbalances the latter.

By providing a local circuit for working fluid which is of greaterspecific weight than the heat transfer fluid in'the system, thelocalcircuit is capable of raising liquid heat transfer fluid systemshown in Fig. 1 to illustrate parts thereof more clearly; and

Fig. 3 is an enlarged fragmentary view similar Since the refrigerationsystem associated with cooling element It does not form a part 'of thisinvention and is merely illustrative, further deseription thereof willnot be made here. If desired, reference may be had to my aforementionedapplication for a description of the operation of the refrigerationsystem, the disclosure of which may be considered to be incorporated inthis application.

The refrigerating effect produced by cooling element 10 is utilized tocool and liquefy a volatile fluid flowing through a coil I! which isarranged about cylinder ll and over which liquid refrigerant flows. Thecoil l5 constitutes the condenser or heat rejecting portion of a heattransfer system forming the subject matter of this invention. a

The heat transfer system includes an evaporator or heat receivingportion l6 which is of the flooded type and at a higher elevation thancondenser IS. The evaporator I6 is disposed in a thermally insulatedspace H and includes a receiver l8 having a looped coil l9 connectedthereto. The evaporator I8 and condenser l5 form part of a closed fluidcircuit which is partly fllled with a suitable volatile liquid, such asmethyl chloride, for example, that evaporatesin evaporator l6 and takesupheat thereby producing cold.

Vapor formed in evaporator l6 flows through a downward extending conduit20 which is connected at .its lower end to a vertical conduit 2|. Thevertical conduit 2| forms part of a local circuit containing mercury orother suitable working fluid having a specific weight greater than thatof the heat transfer fluid. With the introduction of vapor throughconduit 20 into conduit conduit 24 extends.

2|, mercury is raised in a conduit 2| by vapor lift action into theupper part of a chamber 22.

Vapor and mercury are separated in chamber 22, the vapor flowing throughconduit '23 into condenser l5 in which it is cooled and condensed.

The upper end of condenser i5 is closed, whereby condensate will drainand flow by gravity through conduit 23 and accumulate in the lower partof chamber 22.

The slugs of mercury entering chamber 22 gravitate through accumulatedcondensate and enter the upper end of a vertical conduit 24. 'In sodoing, small bodies 25 of condensate the segregated and trapped betweenmercury slugs 26 and moved downwardly in conduit 24. The trapped bodies25 of condensate separate from the mercury in chamber 21 into which thelower end of The separated condensate flows into the lower end of ariser or conduit 28 which is connected at its upper end to evaporatorIS. The lower part of chamber 21 is connected to the lower end ofconduit 2| to complete the circuit for the mercury or working fluid.

The path of flow of vapor from evaporator l8 includes conduit 28, upperpart of conduit 2|, and chamber 22. Conduit 23 and the dead endinterspersed the segregated bodies 25 of volatile condenser l5 in-efiectform an extension of' chamber 22, whereby the vapor is trapped above theliquid level in this chamber. The trapped vapor is condensed incondenser l5, and the path of flow of liquid returned to evaporator H5includes chamber 22, conduit 24, chamber 21, and

conduit 28. The local circuit for circulation of mercury includesconduit 2|, chamber 22, con- -mercury columns will be formed in conduits21,

24, and 28. The common level of mercury in these columns must be higherthan the connection of conduit 28 to conduit 2|.

In starting the system evaporator I6 is charged with volatile liquid,as-at 30, for example. With cooling element Ill operating to produce arefrigerating effect and volatile liquid evaporating in evaporator I8,circulationof mercury in the local circuit is instigated by vapor liftaction.

Since at starting there is no liquid column of heat transfer fluid inconduit 28, the segregated bodies 25 of condensate which separate frommercury in chamber 21 must escape through the mercury column in conduit28. To insure fiow of the separated condensate through this mercurycolumn, condult 28 should be 5 mm. or greater in internal diameter. Asthe column of volatile liquid builds up in conduit 28 the mercury leveltherein recedes and eventually falls to the lower end of conduit 24, asshown in Fig. 2. Conduits 2|" and 24 have an internal diametersufliciently small so that mercury slugs are raised by vapor lift actionin conduit 2| and trapped condensate bodies 25 are lowered in conduit24. The parts making up the mercury circuit are properlyproportionedthat is, conduits 2| and 24 are of such length and conduit28 is connected to conduit 2| at such a level .that, when the mercuryrecedes in conduit 28 upon starting, the mercury will circulate in themanner diagrammatically shown in Fig. 2 and not completely fill themercury circuit.

The column of mercury in conduit 24 may be referred to as the pumpinghead in which are liquid. The weight of the liquid column in conduit 24balances the weight of the riser column of volatile liquid in conduit28. Liquid is raised in conduit 28 under a reaction head formed by thesolid mercury column in conduit 2| which also balances the riser columnof volatile liquid.

With the arrangement shown a relatively small local circuit for aworking fluid having a specific weight greater than the heat transferfluid can v be eifectively employed to raise liquid heat transfer fluidthrough a considerable distance. By providing a mercury column h inconduit 2| which is 18 inches in height, for example, a methyl chlorideliquid column H of 20 feet can be balanced in conduit 28 as indicated inFig. l.

The raising of mercury in cond'uit 2| is due ,to a pressure differencein the system resulting from condenser |5 being at a slightly lowerpressure than evaporator |6.- This may be best explained by assumingthat the pressure in conduit 28 is at a certain value. At a point inconduit 24 somewhat above the connection of conduit 20 to conduit 2|,the pressure is the same as in conduit 20. From this point in conduit 24the pressure decreases upwardly through the liquid, so that the pressurein chamber 22 above the liquid column is less than the pressure inconduit 20. Consequently, there is a pressure difference between chamber22 and conduit 28, whereby liquid is caused to rise due to vapor liftaction. This pressure difference is relatively small.

Due to the relatively large volumes of vapor entering through conduit20, the mercury column in the upper part of conduit 2| is lightened andraised against a small reaction head formed by the liquid column inconduit 24 and chamber 22.

This small reaction head is a part of the weight of liquid in conduit.24 and chamber 22 which balances the weight of the mercury slugs andvapor in conduit 2| above the connection of conduit 28.

- By circulating mercury in the local circuit by vapor lift action,successive bodies 25 of condensate are segregated at the upper end ofconduit 24 and transferred from chamber 22 to chamber 21 which is at aconstantly greater pressure. The pressure in chamber 2'! corresponds tothe height of mercury column h in conduit 2 I, whereby condensate iseffectively returned to evaporator l5 through a considerably greaterdistance H in conduit 28.

To prevent evaporation of volatile liquid in the local circuit, chamber22, conduit 24, chamber 21, and conduit 2| may be embedded in insulationl2 along with cooling element l8. Likewise, vertical conduit 28 may beembedded in insulation 8| to prevent evaporationof volatile liquid inthis conduit.

Inthe embodiment in Figs. l and 2 mercury is raised in conduit 2|against a reaction head formed by liquid in conduit 24 and chamber 22.

diagrammatic view similar to Fig. 2 inwhich 'conduit 20a corresponds toconduit 20, chamber 22a corresponds to chamber 22, and conduits 23a and28a correspond to conduits 23 and 28.

Vapor formed in the evaporator at the upper elevation flows throughconduit 20a into conduit 32 which forms part of the local circuit forcircuchamber 22a. Bodies 25a of condensate are segregated by mercuryslugs 26a at the upper end of conduit 24a, and the segregated bodies 25aof condensate move downwardly in this conduit. At the lower end ofconduit 24a segregated bodies 25a of condensate are relieved and moveupwardly in chamber 21a. The upper part of chamber 21a is connected toconduit 28a through which liquid is raised to the evaporator at theupper elevation.

The lower part of chamber 21a is connected to a vertical conduit-2hrwhich in turn is connected at its upper end to a chamber 33. The lowerpart of chamber 33 is connected to the lower end of conduit 32 tocomplete the local the true spirit and scope of the invention, as

chamber 21a, whereby the mercury will circulate in the mannerdiagrammatically shown in Fig. 3 during operation of the heat transfersystem.

' While several embodiments of'the invention have been shown anddescribed, such variations and modifications are contemplated as fallwithin pointed out in the following What is claimed is: 1. In aheattransfer system including a first circuit partly filled with avolatile liquid and having an evaporation portion at an upper eleclaims.

vation and a condensation portion at a lower circuit for circulation ofmercury. The upper part of chamber 33 is connected by a conduit 34 tothe vapor space in chamber 22a. Chamber 33 may be provided with acharging valve '35 through which the local circuit can be charged withmercury.

Circulation of mercury and heat transfer fluid in the modification inFig. 3 is effected in the same manner as in the embodiment in Figs. 1and 2 and described above. In Fig. 3 the riser column of volatile liquidconduit 28a and chamber 210 is indicated by H and corresponds to theheight H in Fig. 1, This columnof volatile liquid is balanced by aneffective mercury column 71. in the local circuit for mercury.

With variations in the height of the volatile liquid column, variationswill occur in the height of the mercury column in conduit 2 la andcham-- ber 33. The rise and fall of mercuryin chamber .33 will be verysmall since the cross-sectional area of the chamber is relatively largeand con-.

siderably greater than that of chamber 21a. Chamber 33 thereforeservesas a liquid leveling chamber whereby the liquid level therein willonly vary very slightly during operation of the system.

The diflerenc'e in height of mercury in chamber 33 and .inconduit 32represents the reaction head RH by which mercury is raised in conduit32, as indicated in Fig. 3. The weight of the mercury column representedby the reaction head balances the weight of the mercury slugs and vaporraised in conduit 32. Due to the small pressure difierence in conduit20a and chamber 33 resulting from condenser l5 being at a slightly lowerpressure than the evaporator, vapor entering conduit 32 through conduit20a is effective to raise mercury by vapor lift action.

The modification in Fig. 3 is started in a manner similar to thatdescribed above in connection with Fig. 2. Thus, the mercury circuit maybe charged with mercury so that mercury level will be in the lowerpart-of .chamber 33. Upon starting the mercury level recedes invertically extending chamber 21a, in the same manner that it recedes inconduit 28 in Fig. 2, until it eventually falls to the level shown inFig. 3. The chamber 33 is sumciently large to take care of the mercuryreceding in vertically extending formed in said first circuit andcirculation of liquid in said second circuit effects lifting of liquidin said first circuit between said elevations. 2. In a heat transfersystem including a first circuit partly filled with a volatile liquidand having an-evaporation portion and a condensation portion, a, secondcircuit containing a liquid of greater speciflcweight than the volatileliquid and imiscible therewith, means to circulate the liquid of greaterspecific weight in said'second circuit, and means to cause flow ofvolatile liquid from said condensation portion to saidevaporationportion in said first circuit by circulation of the liquidof greaterspecific weight in said first circuit.

3. A method of circulating a volatile fluid which includes condensingvaporized fluid and accumulating the condensate, segregating thecondensate by slugs oi a working fluid having a greater specific weightthan the condensate, so as to produce of a. system partly filled with avolatile liquid and in which liquid is evaporated at an upper elevationand vapor is condensed at a lower elevation, the improvement whichincludes raising a first fluid by vapor-lift action above a liquid levelof a body of a second fluid of less specific weight, separating thevaporirom the first fluid,

condensing the separated vapor above the liquid level of the secondfluid and allowing the condensate to fall by gravity to formthe body ofsecond fluid, producing a liquid column of the first and second fluidsin which bodies of the second fluid are segregated in the first fluid,sepa- 7.

rating the segregated bodies of the second fluid from the flrst fluid inthe lower part of the liquid column, and collecting the separated bodiesto form a riser column of the second fluid in which liquid is raisedunder a reaction head formed by a liquid column of the first fluid.

5. A method of circulating volatile fluid which includes accumulatingcondensate of said fluid in a place of accumulation, segregating thecondensate by slugs of a working liquid of greater specific weight thanthe condensate and immiscible therewith to produce a column of slugs ofthe working liquid and trapped segregated bodies 0f condensate extendingdownward from the accumulated condensate, separating the trapped bodiesof condensate from the working liquid in the lower part of said column,forming a column of the separated condensate, forming a column of theseparated working liquid, continuing transcolumn of condensate to causeupward flow of liquid in this column, taking liquid from the upper endof'said condensate column and evaporating the liquid to form vapor,utilizing said vapor to lift liquid in said column of working liquid-fer of the trapped bodies of condensate to the by vapor lift action toform the slugs of working liquid and cause flow thereof to the place ofcondensate accumulation. v

6. In the art of transferring heat with the aid of a system partlyfilled with a liquid heat transfer fluid, the improvement which includesform-. ing a liquid column oi working fluid of greater specific weightthan the heat transfer fluid, repeatedly segregating bodies of liquidheat transfer fluidby liquid slugs of working fluid at a given levelabove the lower end of said liquid column and lowering such segregatedbodies of heat transfer fluid and slugs of working fluid to the lowerend of the liquid column, separating the segregated bodies ofheatttransfer fluid from vapor-lift action.

working fluid at the lower end of saidliquid column, forming a secondliquid column 'of the separated bodies of heat transfer fluid which'bal-' an'ces said first column, continuing to introduce heat transferfluid from said first column into said second column tofcaus'e upwardflow of liquid 1 in' the latter, evaporating heat transfer fluid takenfrom the upper end of said second column to form vapor, and utilizingthevapor to raise working fluid from the lower end of said first columnupward by vapor lift action to said given level.

7. In a heat transfer system,a circuit containing a volatile fluid andhaving an evaporation causing circulation of the second fluid bycirculation of the first fluid and utilizing vapor formed in said heatabsorption portion to" effect said ALBERT R. moms.

